It is common for databases to contain tables for which the identifying columns consist of a collection of items rather than a single item. For example, whereas a customer table might have a simple key such as customer_id, a product table may have a compound key such as product_category_id+product_subcategory_id+product_id. While the user of a reporting or analysis tool may think of the entity as a single thing (e.g. a product), the compound nature of the identifier (e.g. the compound key) forces the user or client application to track a set of attributes to identify a single instance of the entity (e.g. “the product with product category 1, product subcategory 14 and product id 6”). This requires the user or client application to become familiar with database-specific concepts and/or structures instead of focusing on simply obtaining the answers to the questions using the reporting or other analysis tool. This task can be quite challenging for most knowledge workers and distracts them from focusing on the objective at hand.